<template>
  <div>
    <router-link tag="div" to="/" class="header-abs" v-show="showAbs">
      <div class="iconfont back">&#xe658;</div>
    </router-link>
    <div class="header-fixed" v-show="!showAbs" :style="opacityStyle">
      <router-link to='/'>
        <div class="left"><span class="iconfont back">&#xe658;</span></div>
      </router-link>
      景点详情
    </div>
  </div>
</template>

<script>
export default {
  name: 'DetailHeader',
  data () {
    return {
      showAbs: true,
      opacityStyle: {
        opacity: 0
      }
    }
  },
  methods: {
    handleScroll () {
      const top = document.documentElement.scrollTop || document.body.scrollTop || window.pageYOffset
      if (top > 60) {
        let opacity = top / 140
        opacity = opacity > 1 ? 1 : opacity
        this.opacityStyle = {
          opacity
        }
        this.showAbs = false
      } else {
        this.showAbs = true
      }
    }
  },
  activated () {
    window.addEventListener('scroll', this.handleScroll)
  },
  deactivated () {
    window.removeEventListener('scroll', this.handleScroll)
  }
}
</script>

<style lang="stylus" scoped>
  @import '~styles/varibles.styl'
  .header-abs
    position absolute
    left .2rem
    top .2rem
    width .8rem
    height .8rem
    border-radius .4rem
    background rgba(0, 0, 0, .8)
    z-index 1
    .back
      color #fff
      font-size .8rem
      line-height .8rem
  .header-fixed
    position fixed
    top 0
    left 0
    right 0
    overflow hidden
    height $headerHeight
    line-height $headerHeight
    text-align center
    color #fff
    background $bgColor
    font-size .32rem
    z-index 1
    .left
      position absolute
      width .84rem
      height 100%
      .back
        display block
        font-size 0.6rem
        text-align center
        color #fff
</style>
